Replace Sharp image backend with Photon (#86437)

* refactor: replace sharp image backend with photon

* refactor: remove whatsapp jimp dependency

* chore: remove stale sharp install workarounds

* test: keep image fixtures off photon

* test: use valid prompt image fixtures

* test: account for optimized PNG fixtures

* test: use valid minimax image fixtures

pnpm-workspace.yaml

@@ -100,12 +100,15 @@ allowBuilds:
   koffi: false
   node-llama-cpp: true
   protobufjs: true
-  sharp: true
   tree-sitter-bash: false
   openclaw: true
   "@openclaw/proxyline": true
 
 packageExtensions:
+  baileys:
+    peerDependenciesMeta:
+      sharp:
+        optional: true
   "@earendil-works/pi-coding-agent":
     dependencies:
       strip-ansi: 7.2.0